| 40 | x | ÷ | ( | 40 | + | 200 | ) | = | x | − | 10 100 |
| 方程两边同时乘以: | ( | 40 | + | 200 | ) |
| 40 | x | = | x | ( | 40 | + | 200 | ) | − | 10 100 | ( | 40 | + | 200 | ) |
| 40 | x | = | x | × | 40 | + | x | × | 200 | − | 10 100 | ( | 40 | + | 200 | ) |
| 40 | x | = | 240 | x | − | 10 100 | ( | 40 | + | 200 | ) |
| 40 | x | = | 240 | x | − | 10 100 | × | 40 | − | 10 100 | × | 200 |
| 40 | x | = | 240 | x | − | 4 | − | 20 |
| 40 | x | = | 240 | x | − | 24 |
| 40 | x | − | 240 | x | = | - | 24 |
| - | 200 | x | = | - | 24 |
| 24 | = | 200 | x |
| 200 | x | = | 24 |
| x | = | 24 | ÷ | 200 |
| = | 24 | × | 1 200 |
| = | 3 | × | 1 25 |
| x | = | 3 25 |
| x | = | 0.12 |